You can place weights on both side of weighing balance and you need to measure all weights between 1 and 1000. For example if you have weights 1 and 3,now you can measure 1,3 and 4 like earlier case, and also you can measure 2,by placing 3 on one side and 1 on the side which contain the substance to be weighed. So question again is how many minimum weights and of what denominations you need to measure all weights from 1kg to 1000kg.

A clever robber breaks into a closed bank where he finds a clerk. He asks password of the safe from the clerk while pointing a gun on his forehead. Out of fear, the clerk manages to blurt out, “Every day, the password of the safe is changed. I can help you but please point away the gun as if you kill me, you will never be able to crack the password.

The robber ties the clerk on a chair and insert a cloth in his mouth. He then easily opens the safe after inserting the code and takes all the money before he flees.

I bought three toys for my triplet boys (one for each). I placed the toys in the dark store. One by one each boy went to the store and pick the toy. What is the probability that no boy will choose his own toy?

In a friend's get together party on New Year's Eve, a power cut takes place unexpectedly. When the lights go live again, it is found that Joseph, one of the friends has been stabbed to death. Since no one else had the access to the party, the killer is one of the friends only.

Police are called and they search the surroundings for any evidence, but can't find any. Upon checking the pockets of Joseph's pants, they find a pocket calendar and they find out that it has been marked and can also find some numbers written on it.

You can see the calendar attached with this question.

You don't know the name of the friends who were there at the party. Can you still decipher the name of the killer through the picture?

The numbers that have been written over the calendar are:
12, 4, 8 and 3

A few numbers have been circled under particular months. The curious thing is that the numbers that have been written are the same number of corresponding months under which the dates have been marked.

What we can judge by the overall calendar is that the dates that have been marked may refer to the letters at that position in the month's name. In addition, the written numbers can be the position of those letters. Let's simplify below:

12th month is December
The number marked under December = 5
The fifth letter of December = M

4th month is April
The number marked under April = 4
The fourth letter of April = I

8th month is August
The number marked under August is 6
The sixth letter of August = T

3rd month is March
The numbers marked under March are 4 and 5
The fourth and fifth letter of March = C and H

When you combine the letters, you get the name as MITCH.
Therefore, Mitch is the killer.

A mastermind organized a quiz competition in which six selected candidates were invite namely James Hunt, Ruxandra Bar, Sophia Connors, David Finch, Fred Odea and Brian Miller. A 'special puzzle' was asked to all of them. The first one to answer it was promised for a big award.

After that, the candidates were offered the meal before the mastermind stood up to announce the much awaited result. He started announcing:

Just look at the announcement lines. The first sentence in 'Ok now everybody!' If you take out just the first letter of every word, it will form 'ONE'. In the same manner the second sentence 'The winner of…..' will give form 'TWO' and the third sentence 'The Hardest Riddle Ever Event.' Will form THREE.

Thus the final sentence must form FOUR. There is only one candidate who can suffice with the first two letter and he is Fred Odea. The final sentence of the mastermind must be, 'Fred Odea: Ultimate Riddler!'